title: Polymorphisms of the β2-adrenergic receptor correlated to nocturnal asthma and the response of terbutaline nebulizer.
abstract: BACKGROUND
  Inhaled β(2)-adrenergic receptor (β(2)-AR) agonists are the mainstay of treatment of acute asthma. Polymorphisms of the β(2)-AR, especially codons 16, 27, and 164, may affect the functions of the receptor. This study was conducted to investigate whether different polymorphisms of the β(2)-AR are related to the treatment responses of an inhaled β(2)-AR agonist in children with nocturnal and nonnocturnal asthma in Taiwan.
  
  
  METHODS
  The nocturnal asthma group consisted of 27 children (mean age of 10.3±2.4 years), and the nonnocturnal asthma group consisted of 24 patients (mean age of 9.9±3.0 years). Allele-specific polymerase chain reaction was performed to determine 16, 27, and 164 loci alleles of β(2)-AR genetic polymorphisms, and peak expiratory flow (PEF) was measured before and 1 hour after inhalation of 0.2mg/kg/dose of terbutaline to determine the treatment response in these patients.
  
  
  RESULTS
  The polymorphisms of β(2)-AR 27 but not 16 or 164 were significantly associated with the response to terbutaline nebulizer (p<0.05). The polymorphism of β(2)-AR 16 was associated with nocturnal asthma (p=0.027). The Gly16 allele was more prevalent in the nocturnal asthma group (9/27; 33.3%) than in the nonnocturnal asthma group (3/24; 12.5%). Arg16 allele was less prevalent in the nocturnal asthma (3/27; 11.1%) than in the nonnocturnal asthma group (10/24; 41.7%). There was also a linkage disequilibrium found between β(2)-AR 16 (Arg/Arg) and β(2)-AR 27 (Gln/Gln).
  
  
  CONCLUSIONS
  These findings suggest that polymorphisms of β(2)-AR 16 are related to nocturnal asthma and polymorphisms of β(2)-AR 27 are associated with the variable responses to the inhaled terbutaline in children with nocturnal and nonnocturnal asthma.
authors.affiliation: Department of Pediatrics, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Ming-Yung
authors.initials: MY
authors.lastname: Lee
authors.forename: Shin-Nan
authors.initials: SN
authors.lastname: Cheng
authors.forename: Shyi-Jou
authors.initials: SJ
authors.lastname: Chen
authors.forename: Hui-Ling
authors.initials: HL
authors.lastname: Huang
authors.forename: Chih-Chien
authors.initials: CC
authors.lastname: Wang
authors.forename: Hueng-Chuen
authors.initials: HC
authors.lastname: Fan
mesh_terms: D058666:Adrenergic beta-2 Receptor Agonists / Q000008:administration & dosage / Q000627:therapeutic use*; D000704:Analysis of Variance; D001249:Asthma / Q000188:drug therapy* / Q000235:genetics*; D016009:Chi-Square Distribution; D002648:Child; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D009330:Nebulizers and Vaporizers; D011110:Polymorphism, Genetic; D018343:Receptors, Adrenergic, beta-2 / Q000235:genetics*; D013726:Terbutaline / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D058666:Adrenergic beta-2 Receptor Agonists; D018343:Receptors, Adrenergic, beta-2; D013726:Terbutaline